1. Field of the Invention
The present invention relates to heat sink assemblies, and particularly to a heat sink assembly having high density fins, and the fins can be firmly combined together.
2. Prior art
Advances in microelectronics technology have resulted in electronic devices which process signals and data at unprecedented high speeds. During operation of many contemporary electronic devices such as central processing units (CPUs), large amounts of heat are produced. The heat must be efficiently removed, to prevent the system from becoming unstable or being damaged. Heat sinks are frequently used to dissipate heat from these electronic devices.
However, contemporary CPUs are performing tasks faster and faster and orient to be smaller and smaller in sizes, thus generating more and more heat in relative small volumes. Typical heat sinks are often integrally made by extruding aluminum. The kind of integral heat sink has a base and a plurality of spaced fins extending upwardly from the base. However, the width-to-height ratio of the heat sink is limited by the extruding process. Thus, the effective heat-dissipating area of the heat sink is restricted.
In order to overcome the extruding problem, a heat dissipating structure is provided. Each fin is separately formed and assembled onto a base. The kind of heat dissipating assembly has no limitation of width-to-height ratio of the fins. For example, China Pat. Nos. 01223334.X and 00254564.0, present combined heat sink fins (see FIGS. 4 and 5). Referring to FIG. 4, each fin 100 of China Pat. No. 01223334.X forms a plurality of tabs 110 at upper and lower sides thereof. A plurality of cutouts 120 is defined in each tab 110. The tabs 110 of each fin 100 extend into the cutouts 120 of an adjacent fin. Referring to FIG. 5, each fin 100′ of China Pat. No. 00254564.0 forms two flanges at opposite ends thereof. A plurality of tabs 110′ is formed at each flange. A nub 112′ protrudes from each tab 110′. A plurality of cutouts 120′ is defined in each flange, corresponding to the tabs 110′. The tabs 110′ of each fins 100′ extend into the cutouts 120′ of an adjacent fin. The nub 112′ of each tab 110′ abuts against the adjacent fin therefore preventing the fin 100′ from releasing from the adjacent fin.
However, the combined heat sink fins as shown in FIGS. 4-5 are relatively loose, because the fins are combined together only through tabs extending into cutouts. The heat sink fins combinations are easily deformed and difficult to be held during transportation or assembling process. In addition, combining points of the fins are positioned at lower and upper ends of the fins, which generates an uneven contacting surface between the fins and the heat-conductive base. The uneven contacting surface lowers the heat-conductive efficiency.
An improved heat sink assembly with combined fins, which overcomes the above-mentioned problems, is desired.